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Topic: Looking for sombody to write code for cash payment. (Read 688 times) previous topic - next topic

cedarlakeinstruments

If I were building a small quantity of these, I'd start with a Raspberry Pi. Since it has a higher level of integration than the Arduino and has availability of the many useful Linux libraries it will end up costing less overall.

My basic approach would be to read the flow pulses with the Pi. They should be slow enough that it can keep up without issues (assumption). The entire user interface could then be hosted on the Pi as a web page as you said, but I wouldn't even bother sending data to a server unless they needed to view data from outside the house. For alerts, the app on the Pi would interact with a service like Twilio to send SMS alerts or an external mail server for email alerts.

Doing it this way, a basic proof of concept could be built out in a few hours. Of course, then the last 10% will take 90% of the time and development will drag on for weeks...
Electronics and firmware/software design and assistance. No project too small

vilasalvas

Hi there, thanks for the interest.

I initially started this project wanting a simple plug and play notification of water consumption to simply notify holiday home owners (like me) that there was a problem. But that was over simplified.

Water in Portugal and Spain is quite cheap until you cross a threshold. My normal water bill is 20 Euros PM and a problem one could be 3 - 500 Euros per month!

Project guide.

Pre wired pulsed (reed switch) water meters are cheap and are easily fitted "in line" with the existing official meter, alternatively you could use a decent quality metal Hall flow sensor. The reed switch standard meter is easier to calibrate.

1) Keep a log the official overall water meters reading. This would be the "Overall Reading". At some point the official water meters reading will have to be entered into the code to set the correct starting figure.
2) The meter is read on the 12th of the Month and so a second "Monthly reading" would start from zero on that date and restart the next month, a log of the individual monthly readings would be a nice touch.
3) Thresholds of 5000 and 10,000 Litres per month would create the "Alarm" that would be sent by email and SMS to enable action to be taken if required.
4) GSM is out of the question as there are no cheap even PAYG mobile services in Portugal. The Wi-Fi is OK for 99% of the time.
5) Portugal's power is unreliable but most people including me run 2 or 3 UPS to run routers and CCTV.

It would need to connect to one of the cloud based services e.g. Thingspeak, Cayenne, Twilio.

This guy https://www.youtube.com/watch?v=bMrSYEAVLwM is using a Raspberry Pi Zero W to get the basic idea up and running.

I think the main thing is to keep the product cheap and reliable and simple to use. The end result would be a useful tool for people to keep an eye on water wastage.

Regards

Stewart


cedarlakeinstruments

Hi Stewart:

My main concerns can be summarized in this part of your post:

I think the main thing is to keep the product cheap and reliable and simple to use.
That part right there tells me to expect development costs to exceed $10,000 USD. If you are already expecting that, fine. However, my experience on this board indicates that many posters don't really appreciate what it costs to build out a project for commercialization, so I apologize if it seems that I'm stating the obvious.
Electronics and firmware/software design and assistance. No project too small

wvmarle

That part right there tells me to expect development costs to exceed $10,000 USD.
Depends on how fancy a user interface you want, that's where usually most of the work goes. OP is not asking for app control (or worse: not just Android, but also an app for iOS!), that saves half the budget already.

The expectation of a cheap uncalibrated water flow sensor to be able to reasonably accurately reflect the volume measured by the main calibrated water meter, that's where it really goes wrong. Everything else is quite sensible.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

cedarlakeinstruments

For most professional outfits doing app development, a basic app starts at a hair under $20,000. Or at least that's what I found out a few months ago when I was researching it.

It's hard to find a good iOS developer for under $150/hour it seems. Android is  far less expensive.
Electronics and firmware/software design and assistance. No project too small

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